During laparoscopic surgical procedures and, more particularly, tissue removal procedures, it is desirable to limit the size of the entry incision to minimize the trauma experienced by the patient. In the past, efforts to minimize entry incision size have generally been limited due to the size of the tissue to be removed and the need for access to the tissue.
Morcellators are devices that morcellate, or cut tissue, into smaller pieces to allow for easier removal through small surgical access sites. Prior art morcellators that require a pushing or downward traction operation to cut the tissue present a danger of over extension into tissue that is not to be injured. By way of example, but not limited thereto, during a laparoscopic subtotal hysterectomy, one way of minimizing the danger of this over extension is to amputate the body of the uterus from the cervix prior to morcellation. The amputation of the uterus presents an added risk of injury to other nearby organs, such as the rectum and bowel, as they lie behind the uterus and are difficult to see during uterus amputation. Also, amputation is commonly performed using electrocautery or harmonic scalpel which may cause lateral spread of heat or other energy and can inadvertently cause a burn to the bowel or bladder that may not be realized until days after surgery. Further, amputation of the uterus requires the use of one surgical instrument to amputate the uterus and another surgical instrument to morcellate the uterus with their associated cost and complexity of use.
Some known laparoscopic morcellators utilize graspers that pull tissue into a spinning tubular blade or the spinning blade is pushed into the tissue. These types of instruments have their limitations and dangers associated with their use, non-exclusively including the exposed sharp blade possibly injuring surrounding tissue not intended to be morcellated, discharge of the tissue in a spinning tool, and the difficulty and dangers of placing downward traction into the target tissue. Currently, performing a morcellation through a laparoscope is difficult as there are concerns about a spinning blade being pointing downward toward the bowel. It is undesirable to use a spinning blade that spits cut tissue throughout the abdominal cavity and that allows for cut tissue to drop onto other organs (bowel) in the abdominal cavity. Furthermore, these morcellators require both hands to be used by a surgeon, one to hold the spinning morcellator and the second for the grasper that pulls the tissue through it. The need for two hands to morcellate the tissue limits the surgeon to use his other hand to hold another instrument or the laparoscope. Also, the need for a two handed approach disallows the ability to design the instrument to be used robotically.
In order to make laparoscopic tissue removal safer without the need to first amputate the tissue, morcellators were designed to have a single, looped blade. According to one prior art embodiment, a blade was designed to oscillate, such that the ends of the single looped blade were configured to be rapidly and alternatively pulled on in a proximal direction to impart a sawing motion to the cutting element's distal end. See, for example, U.S. Pat. No. 8,585,727 “Tissue Severing Devices and Methods”. However, while improving upon the safety of prior art morcellators, the efficacy of using a single looped blade knife is markedly diminished by the short distance that the blade travels back and forth to make the cut. Another disadvantage with an oscillating single looped blade is that the targeted tissue moves in the same direction as the blade, making the attempted cut more difficult to perform.
Accordingly there is a need in the art to provide morcellator blade assemblies that are safe for the patient, such that they cut in a proximal direction away from the targeted tissue and nearby organs and oscillate so that they don't splinter and hurl tissue into the surrounding area as with a spinning blade. Additionally the assemblies should also be more efficient at cutting the targeted tissue than a single looped blade. The following disclosure describes cutting devices that solve this need in the art by utilizing reciprocating dual looped blades.
Preferred embodiments are directed to tissue cutting devices comprising: an electric motor configured to be turned on and off; an external tube having an internal channel traversing lengthwise from proximal to distal ends; first and second extension members having proximal and distal ends, left and right sides, and positioned superiorly and inferiorly to one another within the internal channel of the external tube such that they traverse parallel with the length of the external tube, wherein the proximal ends of the extension members are operably coupled to the electric motor that drives straight reciprocating motion of the first and second extension members in alternate proximal and distal directions with respect to each other, such that when the first extension member is pushed distally the second extension member is pulled proximally, and vice versa; an outer looped blade having a first end operably coupled to the first extension member; and a second end operably coupled to the second extension member; and an inner looped blade, positioned proximally and adjacent to the outer looped blade, and having a first end operably coupled to the first extension member and a second end operably coupled to the second extension member; and wherein the outer and inner looped blades are positioned distally to the distal end of the external tube, and configured to reciprocate in alternate clockwise and counter-clockwise directions and in opposite directions with respect to each other as the first and second extension members reciprocate proximally and distally.
Additional embodiments are directed to methods of cutting tissue from a patient comprising: providing the tissue cutting device; inserting the distal end of the external tube into the patient; pulling the external tube proximally exposing the looped blades; turning the electrical motor on to reciprocate the outer and inner looped blades in alternating clockwise and counter-clockwise directions; cutting the tissue from the patient with the reciprocating outer and inner looped blades; pushing the external tube distally over the looped blades; and removing the external tube from the patient.